1. Field of the Invention
The present invention relates generally to endoscopic instruments and, more particularly, to endoscopic instruments for controlled introduction of tubular members in the body and to methods therefor.
2. Description of the Prior Art
Various medical procedures require the introduction of tubular members, such as endotracheal tubes, catheters and cannulas, in the body of a patient. Frequently, distal ends of the tubular members are required to be positioned at sites in the body, including natural or artificial openings or channels in the body, from remote locations that do not permit direct access to and/or observation of the sites in the body. Lack of direct access and/or visibility makes it difficult to accurately position the distal ends of the tubular members at the designated sites from the remote locations, particularly where the tubular members are flexible to conform to the contours of anatomical structure. Depending on the medical procedures being performed, improper positioning of the tubular members can result in various adverse consequences for the patient.
The safety and efficacy of procedures for introducing tubular members in the body can be greatly enhanced with the use of remote or endoscopic visualization wherein a distal end of an endoscope is introduced in the body to permit visualization of the procedures via an eyepiece of the endoscope optically coupled with the image receiving distal end. Introduction of tubular members with the assistance of remote visualization is highly desirable for many various medical procedures; however, even with the assistance of remote visualization, many medical procedures involving introduction of tubular members remain difficult to perform and carry a risk of adverse consequences for the patient. In particular, it is difficult when introducing tubular members in the body to obtain accurate, clear exposure of sites in the body such as body channels or canals in which and/or through which the tubular members are introduced, to introduce the tubular members without trauma or injury to anatomical tissue and to visually inspect or examine the sites in the body. One medical procedure that is difficult to perform even with remote visualization and that is potentially dangerous for patients is endotracheal intubation.
Endotracheal intubation is a frequently utilized, important way to obtain adequate ventilation or respiration in a patient in many circumstances where spontaneous breathing is compromised. In endotracheal intubation, a flexible endotracheal tube is positioned in the patient's trachea or windpipe via the nose, or more commonly, the mouth, to establish a secured airway allowing ventilation or respiration of the patient in various situations including trauma, coma, cardiac arrest, drug-induced depression, acute or chronic pulmonary diseases causing breathing difficulties, cardiopulmonary resuscitation, seizures, respirator care and general anesthesia. With a distal end of the endotracheal tube positioned in the trachea, a proximal end of the endotracheal tube can be coupled with a source of gas or drugs, such as a respirator for supplying oxygen, to permit gas or drugs to be delivered to the lungs via the endotracheal tube.
There are many reasons why endotracheal intubation is difficult to perform and potentially dangerous for the patient. One reason is that the anatomical oropharyngeal passage, i.e. the passage of the mouth and upper throat, is curved and narrow making it difficult for a physician, nurse, anesthetist or other trained medical professional to view and properly guide the distal end of the endotracheal tube into the trachea. Another reason is that the epiglottis normally overlies the glottis opening to the larynx at the upper end of the trachea to prevent the passage of food into the trachea during eating, and the epiglottis must be moved during endotracheal intubation to expose the glottis. A further reason is that, once the glottis is exposed, the endotracheal tube must be accurately passed through the glottis, between the vocal cords and into the trachea, and not inadvertently into the esophagus which is adjacent the trachea and separated therefrom by the corniculus. Yet another reason is that endotracheal intubation must be performed quickly because brain damage and even death of the patient can occur in a matter of several minutes. Exposure of the glottis and introduction of the endotracheal tube in the trachea is very difficult and stressful to perform, even for highly trained medical personnel. When not performed properly, endotracheal intubation can have many adverse consequences for the patient including injury to the front incisors, damage to oropharyngeal, laryngopharyngeal and other tissue, hypoxia, brain damage and death.
Various instruments, such as laryngoscopes, have been proposed to facilitate and improve the safety and efficacy of endotracheal intubation. Such laryngoscopes typically include an endoscope and a blade for manipulating anatomical tissue to expose the glottis. During straightforward or normal endotracheal intubations as typically performed with a laryngoscope, the patient is placed in a supine position on a support surface with the neck fully extended, and the blade is inserted into the patient's mouth to position a distal end or tip of the blade at the base of the tongue. The blade is used to apply gentle upward pressure at the base of the tongue to move the tongue and epiglottis anteriorly to expose the glottis, which is viewed remotely via an eyepiece of the endoscope. With the glottis exposed, the endotracheal tube is advanced along side the blade through the glottis, between the vocal cords and into the trachea. The laryngoscope is then withdrawn leaving the endotracheal tube in the body, and a cuff at a distal end of the endotracheal tube is inflated to secure the endotracheal tube in place in the trachea.
Although straightforward endotracheal intubations with laryngoscopic assistance can be successfully and safely performed in most patients, the procedure remains difficult and stressful to perform even for medical personnel with considerable skill and expertise. Since individual oropharyngeal channels vary greatly among patients in size, shape, and distensibility, significant skill and experience are required to properly position or angle the laryngoscopes and to advance the endotracheal tubes. Additionally, visualization is often impaired by secretions such as blood or vomitus, by anatomical structure or by structure of the conventional laryngoscopes themselves such that the glottis may not be clearly visible even with the assistance of the laryngoscopes. Furthermore, prior art laryngoscopes for endotracheal intubation have many disadvantages in that the endotracheal tubes cannot be advanced in a controlled manner relative to the blades, the endoscopes cannot be advanced in a controlled manner relative to the blades and/or cannot be introduced in the trachea to confirm proper intubation, the distal ends of the endotracheal tubes and/or endoscopes cannot be accurately controlled or guided, the distal ends of the endoscopes cannot be optimally positioned to view the glottis, the components of the instruments are arranged in a manner requiring considerable space such that visualization is obstructed by the instruments themselves and the instruments cause trauma to anatomical tissue, manipulation of the instruments commonly results in damage to oropharyngeal, laryngopharyngeal and other tissue, the instruments are complex and not suitable for use by lesser skilled medical personnel or in emergency situations, the distances that the endotracheal tubes are advanced in the trachea cannot be accurately gauged, operation of the laryngoscopes requires complex maneuvers by both hands of the operator, the head of the patient must be tilted back very far such that neck and spinal injuries can result or be aggravated, the instruments are not suitable for use in what are known as difficult endotracheal intubations and the instruments are not suitable for use in bronchial intubation.
Although straightforward or normal endotracheal intubation is in general difficult to perform and has potential adverse consequences for the patient, there are six particular patient types in which endotracheal intubation is excessively difficult to perform and dangerous for the patient. These patient types include patients having (1) a large tongue relative to the size of the pharynx; (2) poor mobility of the mandible or limited ability to tilt back the head sufficiently, i.e., limited atlantooccipital joint extension; (3) a short muscular neck and a full set of teeth; (4) a receding mandible with obtuse or narrow mandibular angles; (5) a long, arched palate associated with a long, narrow mouth; and, (6) large or protruding incisors and relative maxillary overgrowth or anteriorly located larynx, i.e., a small anterior mandibular space. For the latter patient types, visualization of the glottis is particularly impaired or not possible even with the assistance of remote visualization such that there is an increased risk that the endotracheal tube will be inadvertently placed in the esophagus which can result in hypoxia, brain damage or death due to suffocation. Additionally, rotating or angling conventional laryngoscopes in an effort to visualize and/or expose the glottis in difficult intubations commonly results in injury to the teeth and/or to oropharyngeal and laryngopharyngeal tissue. Since it has been estimated that 20% of endotracheal intubations can be characterized as difficult, a significant problem is presented. This problem is compounded in that most difficult endotracheal intubations are not anticipated but, rather, are identified as difficult after failure to achieve intubation with conventional laryngoscopes such that there is usually little time available before serious consequences will occur.
Various approaches and procedures have been proposed for dealing with unanticipated difficult endotracheal intubations including nasal fiber optic intubation, retrograde intubation, blind nasal intubation, flexible bronchoscopy, tracheostomy and intubation with specialized laryngoscopes. In addition to the disadvantages previously discussed for conventional laryngoscopes and straightforward endotracheal intubation, the foregoing approaches have various additional drawbacks including bleeding, trauma, the need for specialized skill, the need for preparation and implementation time which may be in excess of the time available to prevent brain damage or death of the patient, the need to switch to instruments with which the operator is less familiar, the need for instruments that are complex in structure and use and increased stress for medical personnel performing unanticipated difficult endotracheal intubations. Various other medical procedures and instruments for introducing tubular members in the body share the same drawbacks and disadvantages as straightforward and difficult endotracheal intubations.